Methods and devices for cutting and collecting soft tissue

ABSTRACT

A method of cutting breast tissue for removal may include a step of providing a tissue cutting device having an elongate cutting element, the cutting element being movable between a bowed position and a retracted position, the cutting element having a radially outer side and a radially inner side. The tissue cutting device may be introduced into a breast and the elongate cutting element may be moved to the bowed position. A power source may be coupled to the elongate cutting element; and the cutting element may be rotated after the moving step so that the cutting element cuts the breast tissue. The radially outer side of the cutting element may have a larger surface area for transmitting energy to cut the tissue than the radially inner side.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of prior copending application Ser. No.11/391,791, filed Mar. 28, 2006, which is a divisional of applicationSer. No. 10/272,172, filed Oct. 16, 2002, now U.S. Pat. No. 7,044,956,issued May 16, 2006, which is a continuation-in-part of application Ser.No. 10/189,277, filed on Jul. 3, 2002, the applications and patents ofwhich are hereby incorporated by reference herein in their entiretiesand from which priority is hereby claimed under 35 U.S.C. §120.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention pertains to the field of soft tissue excisionaldevices and methods. In particular, the present invention relates to thefield of devices and methods for excising specimen from soft tissue,such as breast tissue, for example.

2. Description of the Related Art

Breast cancer is a major threat and concern to women. Early detectionand treatment of suspicious or cancerous lesions in the breast has beenshown to improve long-term survival of the patient. The trend is,therefore, to encourage women not only to perform monthly self-breastexamination and obtain a yearly breast examination by a qualifiedphysician, but also to undergo annual screening mammography commencingat age 40. Mammography is the only screening modality available todaythat can detect small, nonpalpable lesions. These nonpalpable lesionsmay appear as opaque densities relative to normal breast parenchyma andfat or as clusters of microcalcifications.

The conventional method for diagnosing, localizing and excisingnonpalpable lesions detected by mammography generally involves atime-consuming, multi-step process. First, the patient goes to theradiology department where the radiologist finds and localizes thelesion either using mammography or ultrasound guidance. Once localized,a radio-opaque wire is inserted into the breast. The distal end of thewire may include a small hook or loop. Ideally, this is placed adjacentto the suspicious area to be biopsied. The patient is then transportedto the operating room. Under general or local anesthesia, the surgeonperforms a procedure called a needle-localized breast biopsy. In theneedle-localized breast biopsy, the surgeon, guided by the wirepreviously placed in the patient's breast, excises a mass of tissuearound the distal end of the wire. The specimen is sent to the radiologydepartment where a specimen radiograph is taken to confirm that thesuspicious lesion is contained within the excised specimen. Meanwhile,the surgeon, patient, anesthesiologist and operating room staff, wait inthe operating room for confirmation of that fact from the radiologistbefore the operation is completed. The suspicious lesion should ideallybe excised in toto with a small margin or rim of normal breast tissue onall sides. Obtaining good margins of normal tissue is extremelydependent upon the skill and experience of the surgeon, and often anexcessively large amount of normal breast tissue is removed to ensurethat the lesion is located within the specimen. This increases the riskof post-operative complications, including bleeding and permanent breastdeformity. As 80% of breast biopsies today are benign, many womenunnecessarily suffer from permanent scarring and deformity from suchbenign breast biopsies.

More recently, less invasive techniques have been developed to sample orbiopsy the suspicious lesions to obtain a histological diagnosis. Thesimplest of the newer techniques is to attempt visualization of thelesion by external ultrasound. If seen by external ultrasound, thelesion can be biopsied while being continuously visualized. Thistechnique allows the physician to see the biopsy needle as it actuallyenters the lesion, thus ensuring that the correct area is sampled.Current sampling systems for use with external ultrasound guidanceinclude a fine needle aspirate, core needle biopsy or vacuum-assistedbiopsy devices.

Another conventional technique localizes the suspicious lesion usingstereotactic digital mammography. The patient is placed prone on aspecial table that includes a hole to allow the designated breast todangle therethrough. The breast is compressed between two mammographyplates, which stabilizes the breast to be biopsied and allows thedigital mammograms to be taken. At least two images are taken at twoangular positions to obtain stereotactic views. The x, y and zcoordinates targeting the lesion are calculated by a computer. Thephysician then aligns a special mechanical stage mounted under the tablethat places the biopsy device into the breast to obtain the sample orsamples. There are believed to be three methods available to biopsylesions using a stereotactic table: (1) fine needle aspiration, (2) coreneedle biopsy and (3) vacuum-assisted core needle biopsy.

Fine needle aspiration uses a small gauge needle, usually 20 to 25gauge, to aspirate a small sample of cells from the lesion or suspiciousarea. The sample is smeared onto slides that are stained and examined bya cytopathologist. In this technique, individual cells in the smears areexamined, and tissue architecture or histology is generally notpreserved. Fine needle aspiration is also very dependent upon the skilland experience of the operator and can result in a high non-diagnosticrate (up to about 83%), due to inadequate sample collection orpreparation.

Core needle biopsy uses a larger size needle, usually 14 gauge to samplethe lesion. Tissue architecture and histology are preserved with thismethod. A side-cutting device, consisting of an inner trough with anouter cutting cannula is attached to a spring-loaded device for a rapidsemi-automated firing action. After the lesion is localized, localanesthetic is instilled and a small incision is made in the skin with ascalpel. The device enters the breast and the needle tip is guided intothe breast up to the targeted lesion. The device is fired. First, theinner cannula containing the trough rapidly penetrates the lesion.Immediately following this, the outer cutting cannula rapidly advancesover the inner cannula cutting a sample of tissue off in the trough. Thewhole device is then removed and the sample retrieved. Multiplepenetrations of the core needle through the breast and into the lesionare required to obtain an adequate sampling of the lesion. Over 10samples have been recommended by some.

The vacuum-assisted breast biopsy system is a larger semi-automatedside-cutting device. It is usually 11 gauge in diameter and is moresophisticated than the core needle biopsy device. Multiple large samplescan be obtained from the lesion without having to reinsert the needleeach time. A vacuum is added to suck the tissue into the trough. Therapid firing action of the spring-loaded core needle device is replacedwith an oscillating outer cannula that cuts the breast tissue off in thetrough. The physician controls the speed at which the outer cannulaadvances over the trough and can rotate the alignment of the trough in aclockwise fashion to obtain multiple samples.

If a fine needle aspirate, needle core biopsy or vacuum-assisted biopsyshows malignancy or a specific benign diagnosis of atypical hyperplasia,then the patient needs to undergo another procedure, the traditionalneedle-localized breast biopsy, to fully excise the area with anadequate margin of normal breast tissue. Sometimes the vacuum-assisteddevice removes the whole targeted lesion. If this occurs, a smalltitanium clip should be placed in the biopsy field. This clip marks thearea if a needle-localized breast biopsy is subsequently required forthe previously mentioned reasons.

Another method of biopsying the suspicious lesion utilizes a largeend-cutting core device measuring 0.5 cm to 2.0 cm in diameter. Thisalso uses the stereotactic table for stabilization and localization.After the lesion coordinates are calculated and local anesthesiainstilled, an incision large enough is permit entry of the bore is madeat the entry site with a scalpel. The breast tissue is cored down to andpast the lesion. Once the specimen is retrieved, the patient is turnedonto her back and the surgeon cauterizes bleeding vessels under directvision. The incision, measuring 0.5 to larger than 2.0 cm is suturedclosed.

The stereotactic table requires awkward positioning of the patient andmay be extremely uncomfortable. The woman must lie prone during theentire procedure, which may be impossible for some patients. Inaddition, the lesion to be biopsied must be in the center working areaof the mammography plates. This may be extremely difficult anduncomfortable for the patient if the lesion is very posterior near thechest wall or high towards the axilla.

The woman is subjected to increased radiation exposure as multipleradiographs are required throughout the course of the procedure to: (1)confirm that the lesion is within the working area of the mammographyplates, (2) obtain the stereotactic coordinates (at least two views),(3) verify the positioning of the biopsy needle prior to obtainingtissue, and (4) verify that the lesion was indeed sampled. If anydifficulty is encountered during the procedure, additional radiographicexposures are required to verify correction of the problem.

Using the core needle biopsy or vacuum-assisted device, bleeding iscontrolled only by manual pressure. Bleeding is generally not an issuewith fine needle aspiration, but is a legitimate complication of theformer two methods. Ecchymoses, breast edema and hematomas can occur.This causes increased post-procedural pain and delays healing. Rarely,the patient may require an emergency operation to control and evacuate atense hematoma.

Another major concern is the possibility of tumor dissemination. Thecore needle biopsy and vacuum-assisted devices both cut into the tumorand carve out multiple samples for examination. While cutting into thetumor, cancerous cells may be dislodged. Cutting across blood vessels atthe same time may allow the freed cancerous cells access to the bloodstream, thus possibly seeding the tumor beyond its original locus. Thelong-term consequences of tumor seeding with the risk of blood bornemetastases are unknown at this time, as the techniques are relativelynew. However, documented instances of cancerous cells seeding locallyinto needle tracks exist. There are numerous reports of metastasesgrowing in needle tracks from previous biopsies of a cancerous mass.Most of these are from lung or liver cancers. However, at least one caseof mucinous carcinoma of the breast growing in a needle track has beenreported. The long-term consequences of neoplasm seeding into needletracks are currently unknown, again because the techniques arerelatively new. Some recommend excision of the entire needle track,including the skin entry site, during the definitive surgical procedurefor a diagnosed cancer, whether it is a lumpectomy or a mastectomy.Others assume that with a lumpectomy, the post-operative radiationtherapy will destroy any displaced cancer cells in the needle track.With the trend towards treating very small cancers only by excision andwithout a post-excision course of radiation therapy, the risk of cancercells metastasizing and growing in needle tracks is very real.

The large core cutting device (0.5 cm to 2.0 cm) generally eliminatesthe risk of needle track seeding as it is designed to excise the lesionintact. A stereotactic table is required with the same inherentawkwardness for the patient, as discussed above. Bleeding is controlled,albeit manually, requiring that the patient wait until the end of theprocedure to be turned over. Compression is used to stabilize the breastand localize the lesions. The breast, however, may be torqued anddistorted between the compression plates such that when the plates areremoved after the biopsy, the large core track left behind may not bestraight, but actually tortuous. This can result in permanent breastdeformity.

The location of the insertion site into the breast is dictated by thepositioning of the breast in the machine and not by the physician. Theentry site is usually away from the cosmetically preferrednipple-areolar complex and is usually located on the more exposed areasof the breast. For the fine needle aspirate, core biopsy andvacuum-assisted devices, the incision is usually very small and the scaralmost unappreciable. However, in the case of the large core biopsydevice (0.5 to 2.0 cm), a large incision is needed. Such a largeincision often results in a non-aesthetically placed scar.

The newer conventional minimally invasive breast biopsy devices haveimproved in some ways the ability to diagnose mammographically detectednonpalpable lesions. These devices give the patient a choice as to howshe wants the diagnosis to be made. Moreover, these devices aresubstantially less expensive than the older traditional needle-localizedbreast biopsy. They are not, however, the final solution. Due to theabove-discussed problems and risks associated with compression,needle-track seeding, blood borne metastases, bleeding, radiationexposure and awkwardness of the stereotactic table, more refined devicesand methods are needed to resolve these issues. Also, the conventionalbiopsy devices do not consider margins in their excisions and if canceris diagnosed, the patient must undergo a needle-localized breastlumpectomy to ensure that adequate margins are removed around thecancer. Devices and methods, therefore, must address the problem ofobtaining adequate margins so that a second procedure is not required.Margins, moreover, cannot be assessed while the breast is beingcompressed.

Commonly assigned U.S. Pat. No. 6,022,362, discloses a novel approach tosoft tissue excisional devices. As disclosed therein, the excisionaldevice includes independently actuable cutting and collection tools. Asshown therein, the device may include a cutting tool attached near thedistal tip of the device. At least a distal portion of the cutting toolis configured to selectively bow out of the window and to retract withinthe window. One embodiment of the device described in this patent alsoincludes an independently actuable tissue collection device that isseparate from the cutting device and that is also externally attachednear the distal end of the device. In this configuration, the tissuecollection device independently collects the tissue severed by thecutting tool as the excisional is rotated and the cutting tool isindependently bowed.

SUMMARY OF THE INVENTION

The present invention, according to one embodiment thereof, is a methodof cutting breast tissue for removal, comprising the steps of: providinga tissue cutting device having an elongate cutting element, the cuttingelement being movable between a bowed position and a retracted position,the cutting element having a radially outer side and a radially innerside; introducing the tissue cutting device into a breast; moving theelongate cutting element to the bowed position; coupling a power sourceto the elongate cutting element; and rotating the cutting element afterthe moving step so that the cutting element cuts the breast tissue, theradially outer side has a larger surface area for transmitting energy tocut the tissue than the radially inner side.

The rotating step may be carried out with the radially outer side havingan exposed part for transmitting energy to the tissue which may be atleast 20% larger than an exposed part of radially inner side fortransmitting energy to the tissue. The rotating step may be carried outwith the radially outer side having an exposed part for transmittingenergy to the tissue which may be at least 35% larger than an exposedpart of radially inner side for transmitting energy to the tissue. Therotating step may be carried out while partially covering at least partof the radially inner side of the cutting element. The rotating step maybe carried out with a cover positioned adjacent the cutting element, thecover also being movable between bowed and retracted positions. Thepreventing step may be carried out with the cover positioned adjacent aradially inner side of the cutting element. The preventing step may becarried out with the portion of the cutting element not transmittingenergy to the tissue being primarily on a trailing side of the cuttingelement. The preventing step may be carried out with a tissue collectionelement preventing contact between the tissue and the portion of thecutting element; and the rotating step may be carried out to severtissue which may be collected by the tissue collection element. Thepreventing step may be carried out by insulating part of the deployedpart of the cutting element to prevent transmission of energy to thetissue.

BRIEF DESCRIPTION OF THE DRAWINGS

For a further understanding of the objects and advantages of the presentinvention, reference should be made to the following detaileddescription, taken in conjunction with the accompanying figures, inwhich:

FIG. 1A is perspective view of an excisional device according to anembodiment of the present invention.

FIG. 1B is a partial enlarged view of the excisional device of FIG. 1A,in which the integrated cut and collect assembly thereof is in anexpanded configuration.

FIG. 1C shows the device of FIG. 1B with an element for retractingtissue away from the ribbon 116.

FIG. 2A is a cross-sectional side view of an excisional device accordingto an embodiment of the present invention.

FIG. 2B is a perspective view of a portion of the integrated cut andcollect assembly of FIG. 2A.

FIG. 2C is a perspective view of the collection portion of theintegrated cut and collect assembly, showing the manner in which theflexible membrane may be attached to the assembly and the outer surfaceof the shaft of the present excisional device, according to anembodiment of the present invention.

FIG. 2D is a cross-sectional view showing the relative positions of theribbons.

FIG. 2E shows an alternative view of FIG. 2D along the cross-section ofFIG. 1B.

FIG. 2F shows another alternative view of FIG. 2D.

FIG. 3 is a perspective view of an excisional device according to anembodiment of the present invention, with the integrated cut and collectassembly in the retracted position.

FIG. 4 shows the excisional device of FIG. 3, with the integrated cutand collect assembly in an expanded position.

FIG. 5 shows the excisional device of FIG. 3, with the integrated cutand collect assembly in a fully expanded position.

FIG. 6 shows an exemplary configuration of the integrated cut andcollect assembly of the present invention, detailing the manner in whichthe collecting portion may be attached to the cutting portion of theintegrated cut and collect assembly.

FIG. 7 shows another exemplary configuration of the integrated cut andcollect assembly of the present invention.

FIG. 8A shows yet another exemplary configuration of the integrated cutand collect assembly of the present invention, detailing the manner inwhich the collecting portion may be attached to the cutting portion ofthe integrated cut and collect assembly.

FIG. 8B shows still another exemplary configuration of the integratedcut and collect assembly of the present invention, detailing the mannerin which the collecting portion may be attached to the cutting portionof the integrated cut and collect assembly.

FIG. 8C shows a perspective and a cross sectional view of still anotherexemplary configuration of the integrated cut and collect assembly ofthe present invention.

FIG. 8D shows yet another exemplary configuration of the integrated cutand collect assembly of the present invention, detailing the manner inwhich the collecting portion may be attached to the cutting portion ofthe integrated cut and collect assembly.

FIG. 8E shows a still further exemplary configuration of the integratedcut and collect assembly of the present invention.

FIG. 9 illustrates aspects of the present method for cutting andcollecting a tissue specimen from a mass of tissue, according to anembodiment of the present invention.

FIG. 10 illustrates further aspects of the present method for cuttingand collecting a tissue specimen from a mass of tissue, according to anembodiment of the present invention.

FIG. 11 illustrates still further aspects of the present method forcutting and collecting a tissue specimen from a mass of tissue,according to an embodiment of the present invention.

FIG. 12 illustrates further aspects of the present method for cuttingand collecting a tissue specimen from a mass of tissue, according to anembodiment of the present invention.

FIG. 13 illustrates further aspects of the present method for cuttingand collecting a tissue specimen from a mass of tissue, according to anembodiment of the present invention.

FIG. 14 illustrates further aspects of the present method for cuttingand collecting a tissue specimen from a mass of tissue, according to anembodiment of the present invention in which the collected and isolated(encapsulated) tissue specimen trails the distal tip of the excisionaldevice as it is retracted from the tissue.

FIG. 15 illustrates further aspects of the present method for cuttingand collecting a tissue specimen from a mass of tissue, according toanother embodiment of the present invention in which the collected andisolated tissue specimen trails the distal end of the excisional deviceas it is retracted from the tissue.

FIG. 16 illustrates still further aspects of the present method forcutting and collecting a tissue specimen from a mass of tissue, in whichthe excisional device containing the tissue specimen has been fullyremoved from the tissue mass from which the specimen was cut, collectedand isolated.

DESCRIPTION OF THE INVENTION

FIG. 1A is a perspective view of an excisional device according to anembodiment of the present invention. As shown, the excisional device 100includes a proximal section 102 that may be configured to fit thephysician's hand. Extending from the proximal section 102 is a shaft 104that may be terminated by a distal tip 106. However, an introducer maybe used for the initial incision, whereupon the tip 106 may be omittedfrom the device 100. The distal tip 106 is configured so as to easilypenetrate a mass of tissue, and may feature curvilinear cutting surfaces(best seen in FIG. 1B). The distal tip 106 may be configured to beenergized by a radio frequency (RF) energy source, supplied via theelectrical cord 122. However, the distal tip 106 need not be energized,as the sharpness of the cutting surfaces of the distal tip 106 isgenerally sufficient to easily penetrate the tissue to the targetexcision site. The distal tip 106 may be configured to be retractableand extendable, so as to reduce trauma. An integrated cut and collectassembly 108 is mounted near the distal tip 106 or near the distal mostportion of the shaft 104. According to the present invention, theintegrated cutting and collection assembly 108 is configured to cut atissue specimen (a piece of tissue or a lesion) from the mass of tissue(such as, for example, breast tissue), to collect the cut specimen andto isolate the cut specimen from the surrounding tissue by, for example,encapsulating the same within a flexible bag-shaped membrane. Althoughthe present invention finds advantageous utility in terms of excisionalprocedures on the female breast, it is understood that the presentinvention is not limited thereto. Indeed, the present methods anddevices may be advantageously employed and deployed within most any massof soft tissue. Moreover, although the present excisional devicedescribed and shown herein is presented as a hand held excisionaldevice, it is to be understood that the proximal section 102 may besuitably modified to fit within a stereotactic unit for automated,semi-automated or manual operation.

According to the present invention, the integrated cut and collectassembly 108 includes a cutting portion and a collection portion thatincludes a flexible membrane 114. The collection portion of integratedcut and collect assembly 108 is attached to the cutting portion. Asshown most clearly in FIG. 1B, the collection portion may be attached tothe cutting portion, according to an embodiment of the presentinvention, by a small ring member 124 encircling both the cuttingportion and part of the collecting portion so as to insure that thecutting and collection portions of the integrated cut and collectassembly 108 move together. As noted above, the cutting portion isconfigured to cut the specimen from the mass of tissue and thecollection portion is configured to collect the cut specimen and toisolate the cut specimen from surrounding tissue. This isolation fromsurrounding tissue, according to the present invention, is carried outby a flexible membrane 114 that forms a part of the collecting portionof the integrated cut and collect assembly 108, as described in detailbelow.

The integrated cut and collect assembly 108 may be mechanically coupledto an actuator 112 such that operation of the actuator 112 causes adeployment of the integrated cut and collect assembly 108 from theretracted position shown in FIG. 1A in which the integrated cut andcollect assembly 108 is at least partially retracted within a trough 120defined within the shaft 104 to a selectable expanded position away fromthe shaft 104, as shown in FIG. 1B. For example, by pushing the actuator112 in the distal direction (i.e., toward the distal tip 106), theintegrated cut and collect assembly 108 transitions from the retractedposition shown in FIG. 1A to a selectable variable expanded positionillustrated in FIG. 1B in which the integrated cut and collect assembly108 bows out radially relative to the longitudinal axis of the shaft 104(i.e., in the direction of arrow 110 in FIG. 1A). The degree of bowing(expansion) of the integrated cut and collect assembly 108 depends uponthe travel imposed upon the actuator 112 by the physician. In thismanner, the physician may match the degree of expansion of theintegrated cut and collect assembly 108 to the size of the targetedlesion or the size of the desired specimen within the mass of tissue.The degree of expansion may be varied at will during the excisionalprocedure by means of direct observation by means of ultrasound or someother imaging or guidance modality disposed within the shaft 104 orexternal to the device 100.

The cutting portion may include a ribbon 116 that is pushed out of thetrough 120 to assume the bowed shape of FIG. 1B. The ribbon may beenergized by an RF energy source so as to efficiently cut the specimenfrom the mass of tissue. A standard, off the shelf and widely availableRF generator, such as a ValleyLab Force FX Generator from ValleyLab ofBoulder, Colo. may advantageously be used to energize the cuttingportion of the integrated cut and collect assembly 108 of the presentinvention, although other RF generators may also be employed to energizethe cutting portion of the integrated cut and collect assembly 108and/or the tip 106 described herein. As the excisional device is rotatedduring the cutting of the specimen, the ribbon 116 of the cuttingportion preferably forms the leading edge of the integrated cut andcollect assembly 108. The collecting portion of the integrated cut andcollect assembly 108 may also include a ribbon that is mechanicallycoupled to the cutting portion thereof, shown in FIG. 1B at referencenumeral 118. The ribbon 118 of the collecting portion may at leastpartially overlap the ribbon 116 of the cutting portion. Attached to thecollecting ribbon 118 and/or to the ribbon 116 of the cutting portion isa flexible membrane 114, which serves to collect and to isolate thecollected specimen by drawing over the cut specimen and encapsulatingsame. The flexible membrane 114 may be shaped as a bag (a container thatis closed on all sides except a selectively openable and closableopening) whose opening may be attached to both the shaft 104 and thecollecting ribbon 118 and/or the ribbon 116 of the cutting portion ofthe integrated cut and collect assembly 108. Although the embodiment ofthe present invention shown in FIGS. 1A and 1B includes a cutting ribbon116 and a collecting ribbon 118, both ribbons are expanded and retractedsubstantially simultaneously as they are mechanically coupled to oneanother to form the integrated cut and collect assembly 108, a singlemechanical expandable and retractable loop. Alternatively, only a singleribbon may be present and the flexible membrane attached directly tosuch single ribbon, as detailed herein below. By virtue of thisconfiguration, when the integrated cut and collect assembly 108 is inthe expanded position (FIG. 1B), the bag is in an open configuration inwhich the tissue cut by the cutting portion is received and collected inthe bag formed by the flexible membrane 114 as the device is rotated.However, when the integrated cut and collect assembly 108 is in theretracted position (FIG. 1A), the opening of the bag formed by theflexible membrane 114 is pinched shut or substantially shut, therebytrapping and encapsulating the collected specimen therein and isolating(or substantially isolating) the collected specimen from the surroundingtissue.

FIG. 2A is a cross-sectional side view of an excisional device accordingto an embodiment of the present invention. As shown, the actuator 112may be mechanically coupled to the integrated cut and collect assembly108 so that when the actuator is pushed in the proximal direction, theintegrated cut and collect assembly 108 retracts within the trough 120defined within the shaft 104. Conversely, when the actuator 112 ispushed in the distal direction, the integrated cut and collect assembly108 is pushed out of the trough 120 and expands out of the trough 120 toassume the bowed shape shown in FIG. 2A. The ribbon or ribbons of theintegrated cut and collect assembly 108 may extend back to the actuator112 through a first lumen 204 defined within the shaft 104 and may beattached to the actuator 112 to thereby enable movement of the actuator112 to expand and retract the integrated cut and collect assembly 108.Alternatively, the ribbon 118 of the collecting portion of theintegrated cut and collect assembly 108 may only extend a fraction ofthe length of the cutting ribbon 116. However, as the two ribbons aremechanically coupled to one another, expansion of the cutting ribbon 116causes the simultaneous expansion of the collecting ribbon 118 withoutthe collecting ribbon 118 being directly attached to the actuator 112.

A second lumen 206 may also be defined within the shaft 104. The secondlumen 206 may be used, for example, to evacuate smoke and/or bodilyfluids from the excision site within the mass of tissue. Alternativelythe second lumen 206 defined within the shaft 104 may be used to delivera pharmaceutical agent to the excisional site, such as, for example, ananesthetic, an analgesic and/or some other agent. Other uses may befound for such lumen. An inflatable balloon 208 may be coupled to theshaft 104. The balloon 208 may be inflated with, for example, a gas(air, an inert gas or carbon dioxide, for example) or a fluid such assaline. The balloon may serve several functions. For example, theballoon 208 may be configured to massage the mass of tissue by pulsatingthe inflation of the balloon, may be configured as a cooling sleeve, maybe configured as a tissue expander, may be configured to stabilize thedevice when inserted in tissue, may be configured to seal the incisionthrough which the device is inserted, to provide hemostatis, and/or toreduce capacitive coupling to reduce tissue heating. The balloon 208 maybe inflated from a lumen defined within the excisional device andsupplied to the device via a suitable port defined in the proximal endof the device. The actuator 112 may define one or more protrusions 212and an interior surface of the device may include correspondingcrenellations that are collectively and cooperatively configured toprovide a number of set stops to the actuator 112 along its travel pathand optionally a tactile feedback for the physician, who can set theintegrated cut and collect assembly 108 to predetermined degrees ofexpansion without looking at the device during the excisional procedure.Indeed, during the procedure, as the physician expands the integratedcut and collect assembly 108, he or she will feel periodic increases inresistance followed by a tactile and/or audible release as theprotrusions 212 slip into the crenellations 210.

FIG. 2B is a perspective view of a detail of the integrated cut andcollect assembly 108 of FIG. 2A. According to this embodiment, thecutting ribbon includes a first cutter ribbon 116A and a second cutterribbon 116B that may be welded (or otherwise attached) to the firstcutter ribbon 116A, as shown by weld 224. Together, the first cutterribbon 116A and the second cutter ribbon 116B constitute the leading(and cutting) edge of the integrated cut and collect assembly 108.Behind this leading edge is the collecting portion of the integrated cutand collect assembly 108. Specifically, behind the leading edge of thecutting portion is disposed the ribbon 118 to which the flexiblemembrane 114 is attached. The ribbon 118 to which the flexible membrane114 is attached may also be welded (or otherwise attached) to the firstcutter ribbon 116A, as also shown at 224. The first ribbon 116A may berelatively wider than the second ribbon 116B, so as to completelyoverlap both the second ribbon 116B and the ribbon 118 to which theflexible membrane 114 is attached. This gives the integrated cut andcollect assembly 108 necessary rigidity, while allowing the secondribbon 116B and the ribbon 118 to be reduced in size, thereby reducingspace and bulk. The three ribbons 116A, 116B and 118 are preferably keptat a voltage equipotential, so as to decrease the possibility of arcingwhen RF power is applied to the integrated cut and collect assembly 108.According to an advantageous embodiment of the present invention, onlythe first ribbon 116A need be coupled to the actuator 112. As the secondribbon 116B and the ribbon 118 are mechanically coupled to the firstribbon 116A, they will move in unison with the first ribbon 116A as theactuator 112 is moved by the physician or the stereotactic unit to whichthe device 100 may be coupled. The device may, of course, omit one ofthe ribbons 116A, 116B such as ribbon 116B as shown in FIGS. 2E and 2Fleaving only ribbon 116A for cutting tissue. The description of ribbon116 as used herein shall apply to ribbon 116A and/or ribbon 116B asshown in FIGS. 2C, 2E and 2F as applicable.

FIG. 2C is a perspective view of the collection portion of theintegrated cut and collect assembly, showing the manner in which theflexible membrane 114 may be attached within the assembly 108 and to theouter surface of the shaft 104 of the present excisional device 100,according to an embodiment of the present invention. As shown therein,the flexible membrane 114 may include a lumen forming portion 224through which the ribbon 118 (see FIG. 2B) is inserted, to providerigidity to the mouth or opening 222 of the collecting portion of theintegrated cut and collect assembly 108. The ribbon 118 is attached tothe cutting ribbon 116 (116A, 116B) so as to expand and retracttherewith under the action of the actuator 112. The flexible membrane114 also includes a shaft attachment tab 220, which is configured toattach the flexible membrane 114 to the shaft 104 of the presentexcisional device. For example, the shaft attachment tab 220 may beattached to the shaft 104 through a mechanically and biologicallyappropriate adhesive. The remainder of the flexible membrane 114 may beshaped as a bag, the opening or mouth 222 thereof being delimited by theshaft attachment tab 220 and the lumen forming portion 225 through whichthe ribbon 118 runs. Therefore, when the actuator 112 causes theintegrated cut and collect assembly 108 to expand, the opening 222 ofthe integrated cut and collect assembly 108 is opened and when theactuator 112 causes the integrated cut and collect assembly 108 toretract at least partially within the shaft 104, the mouth 222 of thebag formed by the flexible membrane 114 closes, effectivelyencapsulating and isolating whatever tissue, specimen or lesion has beencut and collected therein. The tissue is isolated, as the lumen formingportion 224, when the integrated cut and collect assembly 108 is in theretracted state, may be pressed against the shaft 104, therebyinterposing a layer of the flexible membrane 114 between the collectedtissue and the surrounding tissue.

As an alternative, the flexible membrane 114 may be attached to anexterior surface of the device 100 and to a tube defining a lumenrunning at least a portion of the length of the second ribbon 118. Theflexible membrane may be attached thereto by means of an adhesive, forexample. Other means and structures for attaching the flexible membrane114 to the cutting portion of the integrated cut and collect assembly108 are disclosed herein below.

FIG. 2D is a perspective view of a shaft 104 of the present excisionaldevice, showing further aspects thereof. As shown therein, the shaft 104defines a trough 120 near the distal end thereof. Preferably, the trough120 includes a ledge portion 121 that is cut out of the shaft 104. Theledge 121 allows additional room to accommodate the membrane 114 whenthe integrated cut and collect assembly 108 retracts within the trough120. The ledge 121 within the trough 120 enables the integrated cut andcollect assembly 108 to more fully retract within the trough 120 thanwould otherwise be possible without the ledge 121 by providingadditional space for the membrane 114. Without the ledge 121, the bulkof the membrane 114 could hamper the full retraction of the integratedcut and collect assembly 108 into the trough 120. The integrated cut andcollect assembly 108 is preferably at least partially retracted withinthe trough 120 when the cutting portion thereof is first energized,prior to initiating cutting of tissue. This separates the tissue to becut from the cutting portion of the integrated cut and collect assembly108 until the assembly has been sufficiently energized to efficientlycut through the tissue. The trough 120 is also instrumental is allowingthe present excisional device to utilize a standard RF generator (e.g.,one that does not rely upon feedback from an impedance sensor or thelike to vary the applied power), such as the ValleyLab Force FXGenerator discussed above. Keeping the integrated cut and collectassembly 108 at least partially retracted within the trough 120 alsoprevents excessive thermally-induced tissue damage, as all or most ofthe surface area of the cutting portion of the integrated cut andcollect assembly 108 is kept away from the tissue until the cuttingportion is fully energized (i.e., until the current density at thecutting portion of the integrated cut and collect assembly 108 issufficient to initiate and maintain arcing). Other means and structuresfor enabling the RF cutting portion of the integrated cut and collectassembly 108 are disclosed in commonly assigned and co-pendingapplication Ser. No. 09/732,848, filed Dec. 7, 2000, which applicationis hereby incorporated herein in its entirety.

FIGS. 3-5 collectively show the operation of integrated cut and collectassembly of the present excisional device. As shown in FIG. 3, theactuator 112 is in its proximal most position and the integrated cut andcollect assembly 108 mechanically coupled thereto is in thesubstantially retracted position wherein both the cutting and collectingportions thereof are at least partially retracted within through 120defined within the shaft 104. The flexible membrane 114 of thecollecting portion may initially be folded, (at least partially) stowedin the trough 120 defined within the shaft 104, or simply loose. As themembrane 114 is preferably thin, smooth and flexible, it does notsignificantly hamper the insertion of the instrument as it penetratesthe tissue mass. As shown in FIG. 4, sliding the actuator 112 in thedistal direction causes the integrated cut and collect assembly 108 toexpand in the direction shown by arrow 110. This expansion causes thecutting portion of the assembly 108 to bow radially out from the shaft104 and the deployment of the flexible membrane 114 of the collectingportion. As the flexible membrane 114 is attached both to the outersurface of the shaft 104 and to the integrated cut and collect assembly108, expansion of the integrated cut and collect assembly 108 opens themouth of the bag shaped flexible membrane 114 and retraction thereof(FIG. 3) closes the mouth thereof. FIG. 4 shows the device 100 in aconfiguration wherein the actuator 112 is engaged to its distal mostposition and the integrated cut and collect assembly 108 is fullyexpanded. By varying the position of the actuator 112, the physician mayachieve a fine grained control over the deployment of the integrated cutand collect assembly 108 to suit even an irregularly-shaped and sizedspecimen or lesion to be cut, collected, isolated and retrieved.

The integrated cut and collect assembly 108, according to the presentinvention, may include one or more mechanically coupled ribbons orwires. For example, the device 100 may include a first ribbon 116 of thecutting portion and a second ribbon 118 to which the flexible membrane114 is attached. Alternatively, the flexible membrane 114 may beattached to a trailing edge of the ribbon 116 of the cutting portion ofthe integrated cut and collect assembly 108. In such an embodiment, theintegrated cut and collect assembly 108 does not include separate butmechanically coupled cutting and collecting portions, but insteadincludes only a single ribbon 116 or other (RF) cutting element to whichthe flexible membrane 114 is attached. Other methods and means ofattaching the flexible membrane to the cutting portion are disclosedhereunder. Such methods and means may draw upon the physical mechanicalstructure of the cutting portion, the collecting portion, the ribbon 116and/or 118 and the material of the flexible membrane 114.

FIG. 6 shows an exemplary configuration of the integrated cut andcollect assembly of the present invention, detailing one possible mannerin which the collecting portion may be attached to the cutting portionof the integrated cut and collect assembly 108. As shown therein, theintegrated cut and collect assembly 108 may include only a single ribbon116. This single ribbon 116 forms the cutting portion of the assembly108. According to this embodiment, the ribbon 116 may be configured as aflexible tube with a longitudinal slit 606 through which the flexiblemembrane 114 emerges. The flexible membrane 114, according to thisembodiment, may include a locally thicker (bulbous, for example) portion602 that is disposed within the interior lumen 608 defined by thetube-shaped ribbon 116. The slit 606 is oriented such that the flexiblemembrane 114 extends out of the trailing edge 612 of the ribbon 116. Asthe ribbon 116 is expanded and energized and the excisional device 100rotated, the leading edge 610 of the ribbon 116 cuts through the tissue,while the flexible membrane 114 is deployed and trails behind,collecting, isolating and encapsulating the cut tissue. The ribbon 116need not be shaped as a tube, but may assume any shape that efficientlycuts through the tissue and secures the flexible membrane 114 thereto.Moreover, the ribbon need not completely encircle the locally thickerportion 602 of the flexible membrane 114. The ribbon 116 may beadvantageously formed of a conductive and resilient material such asstainless steel, titanium, tungsten or a shape memory metal, such as anickel titanium alloy sold under the name of Nitinol®, for example.

As an alternative to the solid ribbon 116, the cutting portion of theintegrated cut and collect assembly 108 may include or be formed of aplurality of wires or ribbons braided in such a manner as to form thetissue cutting ribbon, as shown at 702 in FIG. 7. To provide additionalrigidity, a central reinforcing ribbon or mandrel 704 may be disposedwithin the interior lumen formed by the braided ribbon 702. As shown inFIG. 7, the locally thicker portion 706 of the flexible membrane 114 maybe formed around the central reinforcing ribbon 704.

FIG. 8A shows another embodiment of the integrated cut and collectassembly 108. As shown, the flexible membrane 114 of the collectingportion may be sandwiched between two flexible plates 806, 808. Rivets,pins and/or welds 808 secure the two plates 804, 806 to one another withthe flexible membrane 114 therebetween. The plates 804, 806 arepreferably sufficiently flexible to selectively assume the retractedshape and the expanded and bowed shape of the integrated cut and collectassembly 108, as shown in FIGS. 3 and 5, respectively. The assembly ofFIG. 8A may also include a solid or braided conductive (shown) ribbon orwire 802. The ribbon 802 may also be sandwiched between the two plates804, 806 and held securely in place. In this case, the ribbon 802defines the leading edge of the integrated cut and collect assembly 108and the flexible membrane 114 the trailing edge thereof. The plates 804,806 and the rivets, welds or pins 808 may be formed of a conductivematerial. In that case, when the ribbon 802 is energized with RF energy,the ribbon 802 and the plates 804, 806 are at a same voltage potential,which prevents or decreases the probability of arcing between the plates804, 806 and the ribbon 802. Alternatively, only the wire or ribbon 802may be formed of a conductive material and the plates 804, 806 and therivets, welds or pins formed of an insulating material. In this case,only then wire or ribbon 802 is energized and cuts through the tissue.

FIG. 8B shows yet another embodiment of the integrated cut and collectassembly 108, in which the collecting portion is directly attached tothe cutting portion thereof. As shown therein, the cutting portion ofthe integrated cut and collect assembly 108 may include a windowedconductive plate 802. This conductive (metal, for example) plate 820 ispreferably a thin plate in which openings 822 are defined. The thinplate 820, according to this embodiment, forms the cutting portion ofthe integrated cut and collect assembly 108. This cutting portion may beformed by bending the plate 820 along the longitudinal axis 824 tosecure the flexible membrane 114 between the free edges thereof. Theleading edge of the integrated cut and collect assembly 108, therefore,may be formed by the bent plate 820 whereas the trailing edge thereofincludes the flexible membrane 114. The openings 822 in the plate 820may facilitate the bending thereof, so as to allow the flexible membrane114 to be securely attached thereto. Crimping of the free edges of theplate 820 and/or an adhesive may be used to secure the flexible membrane114 to the plate 820. The windows or openings 822 may be defined withinthe plate 820 by stamping, through a photoetching technique or bycutting, as those of skill in this art will recognize.

FIG. 8C shows a perspective and a cross sectional view of still anotherexemplary configuration of the integrated cut and collect assembly ofthe present invention. As shown therein, the cutting portion of theintegrated cut and collect assembly 108 may be an elliptical cylinderthat defines an interior lumen 853. The cutting portion 824 may beenergized with RF energy, as discussed above. A mandrel 854 may bedisposed within the cutting portion 824. A slot 828 is defined onlywithin the trailing edge 858, and not within the leading (cutting) edge860 of the cutting portion 851 of the integrated cut and collectassembly 108. The flexible membrane 114 loops around the mandrel andemerges from the cutting portion 824 from the slot 828. The flexiblemembrane 114 may be bonded at 862 after looping around the mandrel 854.Alternatively, the mandrel 854 may be inserted in a lumen formed by theflexible membrane 114. As with the other embodiments discussed relativeto FIGS. 6, 7 and 8, the flexible membrane may also be attached to theouter surface of the shaft 104 by means of a tab, such as shown atreference numeral 220 in FIG. 2C, so as to allow the bag-shaped flexiblemembrane 114 to selectively open and close upon being acted upon byactuator 112.

FIG. 8D shows yet another exemplary configuration of the integrated cutand collect assembly of the present invention, detailing the manner inwhich the collecting portion may be attached to the cutting portion ofthe integrated cut and collect assembly. As shown therein, theintegrated cut and collect assembly 108 may be configured as a singleribbon 876 that defines a cutting portion 872 and a collecting portion874. The single ribbon 876 may be split at least along the length of thetrough 120 of the shaft 104. The distal ends of the cutting portion 872and of the collecting portion 874 may be rejoined or may remainseparate. The membrane 114 may define a lumen in which the free end ofthe collecting portion 874 may be introduced. Alternatively, themembrane 114 may be wrapped around the collecting portion 874 andsecured thereto by means of an adhesive. The cutting portion 872 of thesingle ribbon 876 forms the leading edge of the integrated cut andcollect assembly 108 as the device is rotated within the tissue and thespecimen cut from the surrounding mass of tissue.

FIG. 8E shows another exemplary configuration of the integrated cut andcollect assembly 108 of the present invention. The top figure of FIG. 8Eshows the integrated cut and collect assembly 108 in the retractedposition whereas the bottom figure shows the integrated cut and collectassembly 108 in the expanded position. As shown in the top figure, themembrane 114, when the integrated cut and collect assembly 108 is in theretracted position, is stretched across the trough 120. In thisembodiment, the cutting portion of the integrated cut and collectassembly 108 may include a cutting ribbon 116 that emerges through themembrane 114 through a first slit therethrough and returns to the trough120 through a second slit or opening defined therethrough. The cuttingribbon 116, therefore, is configured to be exposed to the tissue to becut when the device is inserted within the patient and is located on afirst external-facing surface of the membrane 114. The collectingportion of the integrated cut and collect assembly 108 may also includea collecting ribbon 118 that is located on a second surface of themembrane 114. The membrane may be attached to the shaft 104 such thatwhen the integrated cut and collect assembly 108 is expanded in theradial direction relative to the shaft 104, the collecting ribbon 118stretches the membrane 114 and causes the bag-shaped membrane 114 todefine the mouth 222 (see FIG. 2C) of the collecting portion. Afteropening of the mouth or opening 222 by expansion of the integrated cutand collect assembly 108 and the stretching of the membrane 114 andafter tissue has been collecting in the membrane 114, the integrated cutand collect assembly 108 may be retracted at least partially within thetrough 120, causing the membrane 114 to return to the configurationshown in the top drawing of FIG. 8E. That is, the membrane 114 stretchesback over the trough 120, thereby at least partially isolating thecollected specimen from the surrounding tissue. In this embodiment, thecollecting ribbon 118 may not be attached to the membrane 114. Indeed,the collecting ribbon 118 may only act upon the membrane 114 to stretchthe membrane 114 open by pushing on it in the radial direction. When thespecimen has been collected and the integrated cut and collect assemblyintegrated cutting and collecting assembly 108 retracted at leastpartially within the trough 120, the resilient nature of the membrane114 causes the membrane to stretch back over the trough 120.

The foregoing has detailed a number of exemplary embodiments of theintegrated cut and collect assembly 108. Those of skill in the art,however, may devise other alternative configurations and structures tointegrate the cutting and collecting functions of reference numeral 108into a single, mechanically coupled assembly that is actuable by asingle actuator, such as shown at 112. All such alternativeconfigurations, however, are deemed to fall within the purview of thepresent invention.

FIGS. 9-16 show aspects of the present method for isolating a tissuespecimen from surrounding tissue, according to embodiments of thepresent invention. As shown in FIG. 9, the excisional device 100according to an embodiment of the present invention may be insertedthrough the skin 902 (or through the outermost tissue surface of themass or organ from which the specimen is to be collected), either bymaking a prior incision therein or by allowing the distal tip 106 of thedevice 100 to make the initial cut. The distal tip 106 may be energizedwith RF energy during the insertion of the device 100 into the mass oftissue 908, but need not be. Satisfactory results are obtained byequipping the distal tip 106 with sharp blades and a conical shape,without the need for an RF energized tip. The integrated cut and collectassembly 108 should be initially in the retracted position, to enable itto readily penetrate the mass of tissue and advance to the target area(in this exemplary case, lesion 904) with the smallest possible profile.The shaft 104 may then be advanced (either through manual physiciancontrol or by means of a stereotactic setup) to a position wherein theintegrated cut and collect assembly 108 is adjacent the target 904 andthe target is approximately positioned in the middle of the integratedcut and collect assembly 108. As shown in FIG. 10, when the integratedcut and collect assembly 108 of the device 100 is positioned adjacentthe target lesion 904, the integrated cut and collect assembly 108 maybe expanded in the direction indicated by 110 by acting upon theactuator 112, after having fully energized the integrated cut andcollect assembly 108 with RF energy, preferably while the integrated cutand collect assembly 108 is at least partially retracted within thetrough 120. The integrated cut and collect assembly 108 may be expandedto up to its maximum expansion or to a selectable degree of expansion,advantageously under real time ultrasonic guidance and/or under anotherimaging modality. As shown at FIG. 11, the present excisional device 100may then be rotated in the direction indicated by arrow 1102, while theintegrated cut and collect assembly 108 remains energized with RFenergy. In this manner, the leading edge of the RF-energized integratedcut and collect assembly 108 cuts through the tissue. Preferably theintegrated cut and collect assembly 108 is expanded to a sufficientdegree so as to cut a margin of healthy tissue around the target lesion904, so as to decrease the probability of seeding abnormal cells (e.g.,cancerous or pre-cancerous) into and around the excision site and theretraction path. As shown in FIG. 11, as the energized integrated cutand collect assembly 108 is rotated, it cuts around the lesion 904. Asthe trailing edge of the integrated cut and collect assembly 108 hasdeployed the collecting portion thereof, the cut lesion or specimen 904is collected in the open bag formed by the trailing and close endedflexible membrane 114. As shown in FIGS. 12 and 13, the rotation 1102 ofthe device 100 may be continued as needed (preferably under ultrasonicguidance) until the specimen 904 has been at least partially severedfrom the surrounding tissue 906. At this point, the specimen 904 hasbeen at least partially collected within the bag-shaped flexiblemembrane 114 of the collecting portion of the integrated cut and collectassembly 108. As shown at FIG. 14, to fully sever the specimen 904 fromthe surrounding tissue 906, the integrated cut and collect assembly 108,while still RF energized, may be retracted by acting proximally upon theactuator 112, thus causing the integrated cut and collect assembly 108to move in the direction 1104 to capture and encapsulate the specimen904 within the flexible membrane 114. As the bag-shaped flexiblemembrane is now closed, the cut and collected specimen is effectivelyisolated and encapsulated (or substantially isolated and encapsulated)from the surrounding tissue 906. Indeed, the cut and collected specimen904 is now separated from the surrounding tissue by a layer of theflexible membrane 114. The RF to the integrated cut and collect assembly108 may now be turned off.

As shown in FIG. 14, the cut, collected, encapsulated and isolatedspecimen 904 may then be recovered by retracting the device 100 from themass of tissue 908 by moving the device 100 along the directionindicated at 1106. As shown in FIG. 14, the material of the flexiblemembrane 114 may be sufficiently elastic so as to allow the cut,collected and physically isolated specimen to stretch so as to at leastpartially trail the distal tip 106 as the device 100 is retracted alongthe insertion path through the mass of tissue 908, as shown at 1502 inFIG. 14. By configuring the integrated cut and collect assembly 108 soas to allow the specimen filled bag-shaped flexible membrane 114 totrail the distal tip 106, the initial incision into the skin and thediameter of the insertion and retraction path may be kept small, asneither the retraction path nor the incision need accommodate the fullaggregate width of the shaft 104, the integrated cut and collectassembly 108 and the isolated specimen 904.

As shown in FIG. 15, the specimen-filled flexible membrane of thecollecting portion of the integrated cut and collect assembly 108 may beconfigured so that it does not substantially trail the distal tip, oronly does so partially during retraction of the device 100 from the massof tissue from which the specimen was cut. The material of the flexiblemembrane 114 (as detailed below) and the configuration thereof may bechosen so as to achieve the desired behavior during the collecting,isolating and retracting phases of the present method. FIG. 16 shows afully retracted device 100, containing a collected and isolated specimen904 in which the tissue architecture has been maintained substantiallyintact. After full retraction of the device 100 from the mass of tissue,the incision within the skin 904 may be treated and closed according tostandard surgical practices. During the excisional method detailedrelative to FIGS. 9-16, the second lumen 206 (shown in FIG. 2A) withinthe shaft 104 may be used, for example, to evacuate smoke and/or bodilyfluids (e.g., blood) from the excision site within the mass of tissue908. Alternatively the second lumen 206 defined within the shaft 104 maybe used to deliver a pharmaceutical agent to the excisional site, suchas, for example, an anesthetic, an analgesic and/or some other agent.The inflatable balloon 208 shown in FIG. 2A may be may be inflated with,for example, a gas (air or carbon dioxide, for example) or a fluid (suchas saline, for example). The balloon 208 may assist in stabilizing thepresent excisional device within the tissue mass after insertion thereinand/or to provide some degree of hemostasis during the excisionalprocedure.

The flexible membrane 114 is preferably non-conductive and stable athigh temperatures. For example, the material used in the flexiblemembrane should be RF resistant (i.e., have the ability to withstand thetemperatures generated by the RF-energized cutting portion of theintegrated cut and collect assembly integrated cutting and collectingassembly 108). The flexible membrane 11, therefore, should be stable(i.e., acceptably maintains its structural integrity and does notunacceptably melt, deform, burn or lose cohesion, tensile or shearstrength) at temperatures at which the energized cutting portionoperates. According to one embodiment of the present invention, theflexible membrane includes a non-main chain carbon based polymericmaterial, such as a silicone elastomer (such as polydimethylsiloxane,for example) or a silicone-containing elastomer. For example, theflexible membrane 114 of the collecting portion of the integrated cutand collect assembly 108 may include one or more of the followingmaterials: an organic, inorganic or organic-inorganic polymer such as asilicone elastomer or a silicone-containing elastomer, a teraphthalate,a tetrafluoroethylene, a polytetrafluoroethylene, a polyimid, apolyester, a polyolephin, Kevlar® and/or M5®, for example. The flexiblemembrane 114 may have a laminar structure that includes one or morereinforcing layers. Such reinforcing layers may include, for example,any of the above-listed materials and/or polyester, polyurethane orpolyimid, for example. For example, the flexible membrane 114 mayinclude NuSil 10-6640, a material manufactured by NuSil Technology ofCarpinteria, Calif. The thickness of the flexible membrane may be freelychosen according to the desired characteristics of the collectingportion of the integrated cut and collect assembly 108. For example, theflexible membrane 114 may be between about 0.0005 and about 0.1 inches.For example, the flexible membrane 114 may be chosen to have a thicknessbetween about 0.0007 and 0.005 inches. For example, the flexiblemembrane 114 may be selected to have a thickness of between 0.001 and0.015 inches.

When an adhesive is used to secure the flexible membrane to otherstructures of the device or the integrated cut and collect assembly 108,a strong, biologically inert and safe adhesive may be used.Advantageously, a silicone containing or based adhesive or acyanoacrylate containing or based adhesive may be used with goodresults.

In an aspect of the present invention, and as can be appreciated fromthe description and drawings provided herein, the devices and methods ofthe present invention may provide for retraction of tissue away from theribbon 116 which cuts tissue. For example, FIGS. 1B, 1C, 2B, 2C, 2E and2F show the ribbon 118 holding the membrane 114 partially or completelycovering part of the ribbon 116 such as a radially inner side RI. Theribbon 118 and/or a tissue collection assembly 115 prevents tissue fromcontacting part of the radially inner RI side of the cutting ribbon 116and, in particular, the trailing edge TE or trailing side TS of theribbon 116 opposite the cutting side CS. This feature can provideadvantages when starting or re-starting the RF cutting ribbon 116 whenthe ribbon 116 is already within tissue. By reducing the overall surfacearea of the RF cutting ribbon 116 that is exposed to tissue, the currentdensity along other parts of the ribbon 116 may be sufficient to startthe device using a conventional RF generator, optionally with anincreased voltage applied to the ribbon 116. This cannot be said of manyprior art bowed RF cutting elements that provide cutting blades orribbons exposed on both the radially inner and outer sides. Other meansof reducing the surface area of the RF cutting ribbon 116 that isexposed to tissue are disclosed in commonly assigned and copendingapplication Ser. No. 09/732,848, filed Dec. 7, 2000, which applicationis hereby incorporated herein in its entirety.

In another method and device of the present invention, the device mayhave a thickened portion 117 that trails the cutting side CS of theribbon 116. The thickened portion 117 retracts tissue away from theribbon 116 providing the advantage described above. The thickenedportion 117 may be at least two or even three times larger than thethickness of the ribbon 116. The thickened portion 117 may be recessedfrom the cutting side CS by a distance of less than 0.25 inch or evenless than 0.10 inch (FIG. 2E) or about 0.015 inch although anyconfiguration may be used. Referring to FIG. 1B, the thickened portionis provided by the ribbon 118 and membrane 114 which cover the radiallyinner side RI of the ribbon 116 through which energy to cut tissue istransmitted. The thickened portion 117 may also simply be provided bythe membrane 114 itself or another part of the tissue collectionassembly 115. As the membrane is drawn over the tissue being collected,the collapsed membrane 114 can also retract tissue away from the ribbon116.

Referring to FIG. 1C, the device may also provide for retraction oftissue away from the radially outer RO side of the ribbon 116. Thedevice of FIG. 1C is the same as the device of FIG. 1B except that themember 124 has been replaced by an element 125 which extends radiallyoutward from the ribbon 116. The element 125 is essentially a U-shapedsleeve of material having an opening to fit around the trailing side ofthe ribbon 116. The sleeve does not transmit RF energy to cut tissueand, in this sense, insulates the ribbon as well as providing retractionaway from the cutting side CS. Of course, the element 125 providingretraction of tissue may also transmit RF to cut tissue withoutdeparting from various aspects of the invention. The element 125 may beretained by ribbon 116, ribbon 118, member 124, or the tissue collectionassembly 115 such as the membrane 114. Finally, as can be readilyappreciated, the ribbon 118 may be separately movable from the ribbon116 with a separate actuator having similar structure as actuator forribbon 116 thereby allowing the user to selectively cover parts of theribbon 116. In still another aspect of the devices and methods of thepresent invention, the devices may reduce transmission of energy to cuttissue through parts of the cutting ribbon 116 to the tissue so that thecurrent density is increased at other portions thereof to initiate RFcutting. The tissue retraction devices described above also provide agap between the ribbon 116 and tissue which can help initiate RF cuttingby providing an ionizing path between the tissue and ribbon. Forexample, the gap may be simply filled with air, argon, saline or anothersuitable gas or liquid.

Another way of preventing transmission of energy from parts of theribbon 116 to the tissue is to coat the ribbon 116 with a coating 119such as silicone, ceramic and PTFE. The coating 119 may be applied toany part of the ribbon 116. For example, the trailing side of the ribbon116 may be coated to essentially coat half the ribbon 116. By coatingthe ribbon 116 in this manner, half of the cutting ribbon 116 remainsexposed for transmitting cutting energy to the tissue. As used herein,the effective width shall mean the part of the ribbon that is exposed totissue. By coating half the ribbon, for example, the effective width ishalf the width of the ribbon 116. When partially covering, coating orretracting tissue away from the radially inner and/or radially outerside, one side may have an exposed part which is at least 20% larger,and even 35% larger, than an exposed part of the other side. Of course,the radially outer side may also be completely covered, coated or tissuemay be retracted completely away from the radially inner side withoutdeparting from numerous aspects of the invention. For example, if theribbon is recessed only a small amount, such as 0.015 inch, and coveredby the membrane 114 the radially inner side will completely covered asshown in FIG. 2F. Finally, other ways of preventing transmission of RFenergy to the tissue and/or retracting tissue away from the cuttingelement can be appreciated from commonly assigned and copendingapplication Ser. No. 10/098,014, filed on Mar. 14, 2002, and commonlyassigned and copending application Ser. No. 10/066,428, filed on Jan.31, 2002, both applications of which are hereby incorporated herein byreference in their entirety.

In a further aspect of the present invention, the cutting ribbon 116 hasan exposed length which cuts tissue which may be 25, 40 or even 100times larger than the ribbon 116 width or effective width and a lengthto thickness ratio twice as large. The relatively thin, elongate ribbon116 maintains sufficient mechanical stability and integrity to sweepthrough many tissue types. A problem encountered by more robust ribbonsknown in some prior art is that these ribbons may have difficultyinitiating an RF arc within tissue since the ribbons have such largesurface areas in contact with tissue. For a given applied voltage, thelarge surface area reduces the likelihood that the current density willbe sufficient to initiate RF cutting using common RF generators. Therelatively narrow ribbons of the present invention minimize thisproblem. Although the ribbon 116 is relatively small, the presentinvention may be used to remove relatively large tissue masses. In apreferred embodiment, for example, the ribbon 116 has a length of about1.9 inch, a width of about 0.027 inch and a thickness of about 0.012inch, which provides a length to width ratio of about 70 to 1 and alength to thickness ratio of over 158 to 1. Of course, the cuttingelement (ribbon 116) may be configured in a number of different sizeswithout departing from the invention. When using the device to extractrelatively large intact portions of tissue from the breast, the cuttingelement preferably has a tissue-exposed length of about 1.5 to 5.5 inch.The cutting element is preferably made of stainless steel such as 304stainless steel, but may, of course, be made of or include any othersuitable material such as tungsten, titanium or another stainless steel.The device preferably has only one cutting element mounted to the shaft,or stated another way, has one cutting surface or cutting edge, althoughmore cutting elements or ribbons may be used with some aspects of thepresent invention.

While the foregoing detailed description has described preferredembodiments of the present invention, it is to be understood that theabove description is illustrative only and not limiting of the disclosedinvention. For example, the shape of the flexible membrane 114 maydiffer from that described and depicted herein, as may the structure ofthe integrated cut and collect assembly 108. Those of skill in this artwill recognize other alternative embodiments and all such embodimentsare deemed to fall within the scope of the present invention. Thus, thepresent invention should be limited only by the claims as set forthbelow.

1. A method of cutting breast tissue for removal, comprising the stepsof: providing a tissue cutting device having an elongate cuttingelement, the cutting element being movable between a bowed position anda retracted position, the cutting element having a radially outer sideand a radially inner side; introducing the tissue cutting device into abreast; moving the elongate cutting element to the bowed position;coupling a power source to the elongate cutting element; and rotatingthe cutting element after the moving step so that the cutting elementcuts the breast tissue, wherein the radially outer side has a largersurface area for transmitting energy to cut the tissue than the radiallyinner side.
 2. The method of claim 1, wherein: the rotating step iscarried out with the radially outer side having an exposed part fortransmitting energy to the tissue which is at least 20% larger than anexposed part of the radially inner side for transmitting energy to thetissue.
 3. The method of claim 1, wherein: the rotating step is carriedout with the radially outer side having an exposed part for transmittingenergy to the tissue which is at least 35% larger than an exposed partof the radially inner side for transmitting energy to the tissue.
 4. Themethod of claim 1, wherein: the rotating step is carried out whilepartially covering at least part of the radially inner side of thecutting element.
 5. The method of claim 1, wherein: the rotating step iscarried out with a cover positioned adjacent the cutting element, thecover also being movable between bowed and retracted positions.
 6. Themethod of claim 560, wherein: the preventing step is carried out withthe cover positioned adjacent a radially inner side of the cuttingelement.
 7. The method of claim 16, wherein: the preventing step iscarried out with the portion of the cutting element not transmittingenergy to the tissue being primarily on a trailing side of the cuttingelement.
 8. The method of claim 1, wherein: the preventing step iscarried out with a tissue collection element preventing contact betweenthe tissue and the portion of the cutting element; and the rotating stepis carried out to sever tissue which is collected by the tissuecollection element.
 9. The method of claim 1, wherein: the preventingstep is carried out by insulating part of the deployed part of thecutting element to prevent transmission of energy to the tissue.